INDIANAPOLIS -- Online sports betting has blown up in the last few years as it has become legal in 38 states, including Indiana. Americans bet nearly $120 billion on sporting events last year. And with the big Indiana vs. Notre Dame game coming up Friday, it’s worth sharing a warning from financial experts about how sports bets are placed. The Consumer Financial Protection Bureau says you should never use a credit card to make a sports bet. While there are plenty of reasons why that could be dangerous, the CFPB says most credit card companies, including Chase, Discover and American Express, treat online gambling transactions as a cash advance.  That means much higher fees and interest rates than a regular charge on the card. Cash advances usually carry fees that are a certain percentage, or a flat rate, whichever is higher.  That means a $20 bet can carry the same $10 fee as a $200 withdrawal from an ATM.  In addition, a cash advance begins charging interest immediately at much higher rates than a regular charge, often around 30%. The Consumer Financial Protection Bureau says it’s seen a nationwide increase in cash advance fees since online sports betting became widely legal. Instead of credit cards, experts say it’s much better to use a debit card, or an e-wallet like Paypal, Venmo or Apple Pay.  Some credit card companies won’t allow sports betting, while others like Bank of America and Wells Fargo say they may decline internet gambling.